An Indian climber and another from the Philippines became the first mountaineers to die on Mount Everest in the current March-May climbing season of the world’s highest peak, hiking officials said on Friday.

Subrata Ghosh, 45, from India, died on Thursday below the Hillary Step while returning after reaching the 8,849 metre (29,032 feet) peak.

“He refused to descend from below the Hillary Step,” said Bodhraj Bhandari of Nepal’s Snowy Horizon Treks and Expedition organising company.

The Hillary Step is located in the ‘death zone’, an area between 8,000-metre (26,250 ft) high South Col and the summit where the level of natural oxygen is inadequate for survival.

“Efforts are underway to bring his body down to the base camp. The cause of his death will be known only after post mortem,” Bhandari said.

Philipp II Santiago, 45, from the Philippines, died late on Wednesday at the South Col while he was on his way up, said Himal Gautam, a tourism department official.

Santiago was tired when he reached the fourth high camp and died while resting in his tent, Gautam added.

Santiago and Ghose were both members of an international expedition organised by Bhandari.

Nepal has issued 459 permits to climb Everest during the current season that ends in May. Nearly 100 climbers and their guides have already reached the summit this week.

Mountain climbing, trekking and tourism is a source of income and employment for Nepal, one of the poorest countries in the world.

At least 345 people have died on Everest in more than 100 years since summiting expeditions were known to have started, according to the Himalayan data base and hiking officials.